There are various types of securing systems used in vehicle assembly lines. For example, there is a mechanical securing system that uses clamps and fingers, and a suction-securing system that uses vacuum. In the case of the mechanical securing system, since the panels of doors and other such parts are not typically formed with flat surfaces, only a minimal securing area is available. Therefore, stable securing of panels is difficult. Also, because the position of the door panel is altered following the securing operation, the door panel must be put back into its original position, which is a difficult process.
As shown in FIG. 1, a conventional panel-securing system includes a jig-rotating cylinder 10, a clamp cylinder 12, a clamp 14, and a locator 16. Reference numerals 18 and 20 refer to a first hinge and a second hinge, respectively. In an initial state of the conventional panel-securing system, all jigs are reversely rotated by the release of the clamp 14, resulting from the reverse positioning of the clamp cylinder 12 and by the shortening of the jig-rotating cylinder 10.
In the case where a panel 22 of vehicle type A is handled, jigs of vehicle type A are advanced by the elongation of the jig-rotating cylinder 10. With reference to FIG. 2, when the clamp cylinder 12 is operated, the clamp 14 approaches the panel 22. With the continuing advancement of the clamp cylinder 12, the clamp 14 locks onto the panel 22, and the panel 22, secured between the clamp 14 and the locator 16, is transported to a desired location.
In the case of a handling jig mounted on a conventional robot arm or overhead loader, a variety of jigs must be installed in each location in order to secure various panels of differing shapes. A rotating structure therefore must be implemented to prevent interference between the panel and jig. As a result, the overall structure becomes complicated and the assembly has significant weight. For example, in the case of a handling jig used in a door line of an assembly process that produces three different types of vehicles, three different types of jigs must be provided at each master control point as shown in FIG. 3.
It is therefore necessary, with the conventional panel-securing system for various vehicle types, to use a different set of clamps and fingers for every type of vehicle, as well as separate cylinders to drive the clamps and fingers. The large number of clamps, fingers and cylinders increases overall manufacturing cost and requires crowding of parts into small areas. Further, a shut-down period is required when changing vehicle type so that changes in the securing system can be made. Finally, the conventional panel-securing system is slow in operation as a result of its increased weight, thereby slowing the overall production process.